1. Field of the Invention
The present patent application relates to a steam wand for professional coffee machines as well as home coffee machines.
The peculiarities and advantages of the present invention will become evident after a short description of the prior art.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
It is known that all coffee machines, and particularly professional machines used in bars, are provided with at least one “steam wand”. Such a term usually indicates a small rigid metal tube that delivers pressurized steam produced by a boiler mounted inside the coffee machine.
As it is known, the forced hot steam jet delivered by such a steam wand is used to instantaneously heat milk or other liquids used to prepare drinks. The main use of the steam wand of any coffee machine is the preparation of cappuccinos, when it is necessary to forth milk in order to obtain a fluffy foam.
However, it must be noted that, in spite of their huge popularity, traditional steam wands are not perfectly satisfactory from the functional viewpoint, given the fact that milk can be correctly frothed only if the operator follows a specific, empiric procedure as illustrated below.
It must be noted that such a procedure largely depends on the operator's experience and skill because traditional steam wands are not able to guarantee excellent milk frothing on a regular basis regardless of the operator.
For a better understanding of the problem, it must be noted that a traditional steam wand usually ends with an enlarged head, whereon one or more steam dispensing nozzles are obtained.
In particular, said nozzles are turned downwards with the same inclination and have a radial direction with respect 5 to the axis of the steam wand, i.e. the axes of the dispensing nozzles intersect the axis of the axial conduit obtained inside the steam wand that is actually used to feed the nozzles.
However, similar nozzles divide the hot steam flow that flows at high pressure inside the steam wand into one or more jets, substantially with the same size.
In case of a similar configuration of a typical steam wand, the operator must follow the procedure illustrated below to froth the milk contained in a metal jug.
The operator must insert the head of the steam wand in the jug, making sure it is immersed deeply into the milk, and then dispense forced hot steam through the steam wand. So the foam will progressively increase the level of milk in the jug; for this reason the operator must lower the jug slowly, while making sure that the head of the steam wand remains always immersed.
This first step of the milk frothing procedure is completed when the milk temperature reaches 35-37° C. It must be noted that the achievement of such a temperature is instantaneously detected by the operator, without using a thermometer, as soon as the operator feels that the temperature of the jug that contains the milk to be frothed tends to exceed the temperature of the hand that holds the handle of the milk jug.
Once this first operation has been completed, the milk foam must be compacted in order to achieve a fine texture and a glossy surface. To do that, while still keeping the head of the steam wand immersed in the milk and dispensing steam, the operator must slightly tilt the jug in order to create a fast whirl in the milk mass that will compact the foam.
The operator must stop dispensing steam as soon as the milk has reached a temperature of 65-67° C. Also in this case, an expert operator can understand that such a temperature has been reached, without using a thermometer, as soon as he feels that the jug is becoming too hot to be held with bare hands.
The best result of such a milk frothing operation is not always guaranteed, it being dependent on the operator's experience and skill.